CD8A and gastric cancer: Kim and colleagues reported that in the mouse GC model, 5-FU and oxaliplatin reduced the numbers of myeloid-derived suppressor cells to increase the anti-GC efficacy of the PD-1 inhibitor and promote tumor infiltration by CD8+ T cells.418 However, these chemotherapeutic agents might also mediate induction of PD-L1 expression in tumor cells leading to tumorigenesis of gastric epithelial cells and tumor progression.418